Red lily beetleCommon name:  Lily beetle, red lily beetle or scarlet lily beetle

Latin name: Lilioceris lilii (L.)

Description: Adults are 8mm long, bright red with a black head and legs. Eggs are 1mm long and orange-red. Larvae have orange bodies with black heads, but are normally covered with their own slimy black excrement. Fully grown larvae are 8-10mm long. Adults and larvae defoliate lilies (Lilium and Cardiocrinum) and fritillaries (Fritillaria).

Lily beetle distribution in the UK at December 2014. Produced using Dmap©Distribution:The lily beetle is native to Eurasia but not the UK. In 1939 an established colony was discovered in a private garden at Chobham, Surrey. At first it spread slowly, expanding into Hampshire, Middlesex, Wiltshire, Dorset, Hertfordshire and Oxfordshire by 1990, but over the next two decades the beetle spread much more rapidly and by 2009 it had been found in all English counties. The beetle was reported for the first time from Scotland and Northern Ireland in 2002 where it is becoming widespread. The first report of the beetle from the Republic of Ireland was received in 2010 and the beetle is now established in the country.
Lily beetle is an established non-native in North America where it is spreading and is now found almost everywhere that lilies are grown in the northern hemisphere. Read more about the situation in North America.

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Thank you to those who took part in the survey in 2008 to 2014. More than 11,600 records of the beetle have been received, many from new areas greatly adding to our knowledge of this pest.

Host range
Both adults and larvae damage lilies (Lilium and Cardiocrinum spp and hybrids) and fritillaries (Fritillaria spp.) primarily by defoliation, although in heavy infestations the flowers, seed capsules and stems can also be eaten. Although adult beetles have occasionally been found on other plant species, only lilies and fritillaries are true hosts, on which eggs are laid and larvae develop.

As part of RHS research, the susceptibility of six different lilies was assessed (one species and five hybrids). Results from the trial indicated that the species lily Lilium regale was less susceptible than the hybrids. The results from the trial have been published - see Salisbury A, Clark S J, Powell W, and Hardie, J. 2010. Susceptibility of six Lilium to damage by the lily beetle, Lilioceris lilii (Coleoptera; Chrysomelidae). Annals of Applied Biology 156: 103–110.

One variety of Lilium is currently advertised as lily beetle tolerant, Lilium ‘Defender Pink’

Odour-mediated behaviour
An RHS-HDC funded PhD research project indicated that in the spring female beetles are able to locate lilies by odour alone, and that the beetles preferentially move towards the odour of plants already infested with other beetles. Such research is vital to progress towards developing a control method using odours (volatile chemicals) to which the beetle responds. This part of the work was published in 2012 - Salisbury, A., Cook, S.M., Powell, W. & Hardie, J. 2012. Odour-mediated orientation behaviour of the lily beetle (Lilioceris lilii). Physiological Entomology 37:97-102

Control
At present gardeners rely on pesticides or hand picking to control this pest, but the long period over which the adults are active (March to October), can make this difficult. Pesticides for use against lily beetle include those containing pyrethrum, deltamethrin, thiacloprid, or acetamiprid. To achieve adequate control in areas where the pest is abundant may require measures to be repeated during spring and summer.

More information
RHS Advice on Lily beetle 
Comprehensive scientific literature review. The biology of the lily beetle Lilioceris lilii (Scopoli) (507kB pdf)
RHS entomology publications

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